After the vast emptiness of the Turbine Hall, the Chinese artist Ai Weiwei will on Friday fill a London space that could not be more of a contrast: a white cube that is precisely 40cm by 40cm by 40cm.

Ai's work, a cactus and a crab, goes on display for a month at a micro space in the Pippy Houldsworth Gallery in London. "It is a very exciting moment for us," said Houldsworth. "He is a very inspirational person. We want to do anything that can help him and anything that can help get his message across."

The artist is prevented from leaving China by the authorities but is not in jail after his release last year. Ai was jailed for three months on suspicion of "economic crimes", although his family and supporters say it was retaliation for his social and political activism.

He is keen for people to make their own interpretation of his latest work, called A Living Sculpture, but it is hard not to read parallels between the piece and the artist's own situation. There is the living cactus – hardy, resilient, prickly – surviving in a confined space under the glare of a spotlight. Then there is the small crab with its nasty claws, making a move on its spiky partner.

The gallery has had to source the cactus, a Ferocactus, which turned out more tricky and time-consuming than it expected.

"It was not that easy at all," said the gallery's Carsten Recksik who spent a large part of last month on the telephone trying to find a suitable specimen. "Ai was very specific on the variety. I was calling dozens, hundreds of garden shops. I'm not really into plants but I am a bit now – it's fascinating."

The result is a 15-year-old cactus, they think. "It's difficult to tell," said Recksik.

The space is a kind of black incision in the wall within which there is a suspended, brightly lit box. "We commission emerging and established artists to do whatever they want in the box," said Houldsworth. "Whether they want to do a conceptual piece or want to take it away to work in their studio or paint on it. It is a terribly difficult space but very exciting."

Ai, who is a cacti collector, came to the attention of the wider British public when he filled Tate Modern's Turbine Hall with 100m porcelain sunflower seeds. His work will also be on display this summer when he designs the Serpentine Gallery pavilion with the architects Herzog & de Meuron, with whom he collaborated to design the Beijing Olympics' Birds Nest stadium.

• Ai Weiwei's A Living Sculpture is at the Pippy Houldsworth Gallery, 27 April - 26 May 2012.

• This article was amended on 3 May 2012 to correct the name of the cactus used in Ai Weiwei's work after the gallery updated its information.